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采用美国Li-COR公司生产的LI-6400便携式光合作用测量系统,在2008和2009年生长季节对极端干旱区额济纳绿洲多枝柽柳(Tamarix ramosissima Ledeb.)叶片的净光合速率(Pn)与蒸腾速率(Tr)、胞间CO2浓度(Ci)随光照强度的变化。结果表明:胞间CO2浓度(Ci)随光照强度增强而减小;净光合速率(Pn)与蒸腾速率(Tr)均随光照强度增强而增大。在达到光饱和点后净光合速率(Pn)随光照强度增强而逐渐减小;水分利用效率(WUE)随光照强度增强呈先增大,达到最大值后又逐渐减小。蒸腾速率(Tr)和胞间CO2浓度(Ci)随CO2浓度升高而增大;净光合速率(Pn)和水分利用效率(WUE)在CO2浓度为200~600μmol/mol时随CO2浓度升高而增大,当CO2浓度升高至1 000μmol/mol时,水分利用效率(WUE)先增大后减小。
The LI-6400 portable photosynthesis system produced by Li-COR company was used to measure the net photosynthetic rate (Pn) and transpiration rate of Tamarix ramosissima Ledeb. In the growing season of 2008 and 2009 in the extremely arid region. (Tr), intercellular CO2 concentration (Ci) with light intensity changes. The results showed that the intercellular CO2 concentration (Ci) decreased with the increase of light intensity. The net photosynthetic rate (Pn) and transpiration rate (Tr) increased with the light intensity increasing. The net photosynthetic rate (Pn) decreased with the increase of light intensity when the light saturation point was reached. The water use efficiency (WUE) increased first and then decreased with the increase of light intensity. The transpiration rate (Tr) and intercellular CO2 concentration (Ci) increased with the increase of CO2 concentration. The net photosynthetic rate (Pn) and water use efficiency (WUE) increased with the CO2 concentration at CO2 concentration of 200-600 μmol / When the CO2 concentration increased to 1 000 μmol / mol, the water use efficiency (WUE) first increased and then decreased.